Dan Charles

Arkansas is on the verge of banning the use, during the growing season, of a Monsanto-backed weedkiller that has been blamed for damaging millions of acres of crops in neighboring farms this year.

The weedkiller is called dicamba. It can be sprayed on soybeans and cotton that have been genetically modified to tolerate it. But not all farmers plant those new seeds. And across the Midwest, farmers that don't use the herbicide are blaming their dicamba-spraying neighbors for widespread damage to their crops — and increasingly, to wild vegetation.

When the worst of Irma's fury had passed, Gene McAvoy hit the road to inspect citrus groves and vegetable fields. McAvoy is a specialist on vegetable farming at the University of Florida's extension office in the town of LaBelle, in the middle of one of the country's biggest concentrations of vegetable and citrus farms.

It took a direct hit from the storm. "The eyewall came right over our main production area," McAvoy says.

Earlier this week, as torrents of rain fell on Houston, Craig Boyan, CEO of the H-E-B supermarket chain, went on a video-taped tour of his company's emergency operations center in San Antonio, Texas. The company later made the video available online.